CO₂ savings are estimated using avoided-emission factors — the greenhouse gas that would have been produced by making the same materials from virgin resources:
| Material | Factor | Source |
|---|---|---|
| Paper & Cardboard | 0.9 kg CO₂/kg | DEFF South Africa / IPCC |
| Aluminium | 9.0 kg CO₂/kg | Int'l Aluminium Institute |
| Plastics | 1.6 kg CO₂/kg | WRAP / IPCC AR6 |
| Glass | 0.315 kg CO₂/kg | British Glass / IPCC |
Formula: CO₂ saved = Σ (kg collected per material × emission factor).
Equivalencies: 1 car-year ≈ 4 600 kg CO₂ (US EPA); 1 tree-year ≈ 21 kg CO₂ (IPCC); 1 kWh ≈ 0.5 kg CO₂ (SA grid average).
These are estimates for sustainability reporting. Actual savings vary based on material quality, transport distances, and recycler processing efficiency.